Year	Percent of Total
1960-01-01	44.7378978739300
1961-01-01	45.1929454839750
1962-01-01	45.7792545969092
1963-01-01	46.3632051076037
1964-01-01	46.7308713918075
1965-01-01	46.7946491052584
1966-01-01	47.0768982070662
1967-01-01	47.0339103927595
1968-01-01	46.7854810186286
1969-01-01	46.5158389024110
1970-01-01	46.3288147463963
1971-01-01	46.4118543685831
1972-01-01	46.4956755859263
1973-01-01	46.5839053800790
1974-01-01	46.6469806422990
1975-01-01	46.6732418012467
1976-01-01	46.9515556074759
1977-01-01	47.1385642187641
1978-01-01	47.2637836943406
1979-01-01	47.3572187118448
1980-01-01	47.4350328671094
1981-01-01	47.7273585276100
1982-01-01	47.9108042073204
1983-01-01	48.0171598385027
1984-01-01	48.0645199269343
1985-01-01	48.0487305074294
1986-01-01	48.2217851656395
1987-01-01	48.3441383286618
1988-01-01	48.4001431999811
1989-01-01	48.3771653514680
1990-01-01	48.2853098495075
1991-01-01	48.3909119456124
1992-01-01	48.3597714280427
1993-01-01	48.2408931720071
1994-01-01	48.0778577100520
1995-01-01	47.8825346762358
1996-01-01	47.8884211747981
1997-01-01	47.8324745720072
1998-01-01	47.7266462155898
1999-01-01	47.5878141409723
2000-01-01	47.4395660487209
2001-01-01	47.4485767342983
2002-01-01	47.4140011560010
2003-01-01	47.3556625699342
2004-01-01	47.2858385019683
2005-01-01	47.2100660875706
2006-01-01	47.2971635787056
2007-01-01	47.3397617556638
2008-01-01	47.3512713114596
2009-01-01	47.3396161794292
2010-01-01	47.3062990660628
2011-01-01	47.3625171433568
2012-01-01	47.3568455719303
2013-01-01	47.3033278278536
2014-01-01	47.2109546692097
2015-01-01	47.0803022544891
2016-01-01	46.9596938070235
2017-01-01	46.8078621435202